ImageMagick as well! At a big social media company I used to work at [1], they were spending a not-insignificant amount of money (in the millions) to their CDN/caching provider just to have images resized and converted to PNG and WebP. I am pretty sure all this CDN was doing was running the image through ImageMagick or GraphicsMagick and calling it a day, and charging absurd quantities of money to do it.

[1] it's not hard to find my employment history but I ask you not to say it publicly here